1. Field of the Invention
The invention relates to a lens assembly, more particularly to a miniaturized lens assembly.
2. Description of the Related Art
Referring to FIGS. 1, 2 and 3, a conventional lens assembly includes a shell unit 1, a lens unit 2 received in the shell unit 1, and a motor 3 for actuating the lens unit 2.
The shell unit 1 has a peripheral wall 101 and a guiding groove 102 in the peripheral wall 101.
The lens unit 2 has a front lens portion 4, a rear lens portion 5 opposite to the front lens portion 4 along a longitudinal axis (X), a large diaphragm plate 6 mounted between the front lens portion 4 and the rear lens portion 5, a small diaphragm plate 7 mounted pivotally between the front lens portion 4 and the rear lens portion 5 and rotatable relative to the large diaphragm plate 6, a shutter plate 8 mounted pivotally between the front lens portion 4 and the rear lens portion 5 and rotatable relative to the large diaphragm plate 6, a connecting member 9 mounted pivotally on the shell unit 1 and connected to the shutter plate 8, and an electromagnetic actuator 901 mounted on the shell unit 1 for actuating the connecting member 9.
The large diaphragm plate 6 has a large aperture 601 along the longitudinal axis (X). The small diaphragm plate 7 has a coupling end portion 701 movably anchored in the guiding groove 102 of the shell unit 1, and a small aperture 702 for overlapping or moving away from the large aperture 601. The shutter plate 8 has an actuated portion 801 and a shading portion 802 for covering or moving away from the large aperture 601. The connecting member 9 is mounted outside the front lens portion 4, and has a pivoting portion 902, an actuated end portion 903 extending from the pivoting portion 902 and actuated by the electromagnetic actuator 901, and a transmitting end portion 904 opposite to the actuated end portion 903 and coupled to the actuated portion 801.
When the motor 3 is actuated to move the lens unit 2 along the longitudinal axis (X), the switching between the large and small apertures 601,702 can be achieved through the action of the coupling end portion 701 in the guiding groove 102. As shown in FIGS. 2 and 4, when the actuated end portion 903 of the connecting member 9 is actuated by the electromagnetic actuator 901, the actuated portion 801 of the shutter plate 8 can be actuated by the transmitting end portion 904 so that the shading portion 802 of the shutter plate 8 can be moved relative to the large aperture 601 to shade or move away from the latter so as to achieve the purpose of controlling the shutter plate 8.
Although the switching between the large and small apertures 601,702 and the control of the shutter plate 8 can be achieved in the aforesaid conventional lens assembly, the following disadvantages are encountered:
1. Since the shutter plate 8 is controlled by the pivotal movement of the connecting member 9 actuated by the electromagnetic actuator 901, the volume occupied thereby is relatively large.
2. Since the switching between the large and small apertures 601,702 is conducted by the cooperation of the small diaphragm plate 7 and the guiding groove 102 of the shell unit 1, and since the control of the shutter plate 8 is actuated by the pivotal movement of the connecting member 9, testing of the lens unit 2 is conducted after the lens unit 2 is installed on the shell unit 1. If the lens unit 2 needs to be modified or adjusted after the test, it is required to disassemble the same from the shell unit 1. Therefore, the process for making the conventional lens assembly is troublesome.
3. The transmitting end portion 904 of the connecting member 9 should have a length sufficient for the operation of the lens unit 2, and should be inserted between the front and rear lens portions 4,5 in order to connect to the actuated portion 801 of the shutter plate 8 interposed between the front and rear lens portions 4,5. Therefore, the installation of the conventional lens assembly is relatively complicated.
4. The accuracy of the action of the shutter plate 8 may be affected by the accumulated tolerance of the amount of the magnetic affinity of the electromagnetic actuator 901, the clearance between the transmitting end portion 904 of the connecting member 9 and the shutter plate 8, the clearance between the pivoting portion 902 of the connecting member 9 and the shell unit 1, and the like.